4K60Hz HDR Hyperion Setup

Hi everyone, I've just recently stumbled upon the hyperion project.
I am very interested to build my own ambilight setup but I couldn't really gather enough information for what I was trying to do.
Essentially, I'd like my setup to work with any HDMI signal and as stated in the title, I want to have full 4K 60Hz HDR experience on compatible devices (e.g. Watching Netflix with an Xbox One S).

As you can see I'm still missing a 4K to RCA signal converter/downscaler.
The only one I could find is the super expensive HDfury Linker (http://hdfury.com/product/linker-4k60-444-600mhz-scaler/) but I am not ready to spent that money on a signal converter.
Are there any other options to get my setup to work? Would it work, if I would buy 2 separate signal converters, 4K -> 1080P and 1080P -> RCA?